package com.lihh.demo003;

import java.util.HashMap;

public class Main01 {
  public static void main(String[] args) {
    StringBuffer stringBuffer = new StringBuffer();
    stringBuffer.append("a");
    
    StringBuilder stringBuilder = new StringBuilder();
    stringBuilder.append("a");
    
    HashMap<String, String> stringStringHashMap = new HashMap<>();
    
  }
}
